1. Field of the Invention
The present invention relates to a semiconductor device suitably applied to, for example, vehicles such as passenger cars, trucks, or buses, household equipment, or industrial equipment.
2. Description of Related Art
There are semiconductor devices obtained by packaging a semiconductor element such as an insulated gate bipolar transistor (IGBT) or a MOSFET into a stacked structure together with a metal block and a radiator plate. For example, an emitter electrode made of aluminum is formed on the surface of a semiconductor substrate on which an IGBT is formed, a gate wiring layer is formed via a LOCOS oxide film and an insulating film, and the gate wiring layer is covered with a protective film to prevent short-circuiting with the emitter electrode.
When a crack develops in the protective film of such a semiconductor device for some reason, it is no longer possible to ensure the insulation mentioned above. Accordingly, as disclosed in, for example, Japanese Patent Application Publication No. 2011-066371 (JP 2011-066371 A), a second protective film made of a material different from that of a first protective film formed on the gate wiring of a semiconductor element is formed around the first protective film, thereby preventing a crack that has developed in the second protective film from reaching the first protective film.
However, the above-mentioned technique has the following problem. That is, depending on the material of the metal block stacked on the semiconductor element, a crack develops in the protective film owing to burrs generated in the manufacturing process of the metal block, which again may make it impossible to ensure insulation.